What energy level is typically used for the initial defibrillation shock with biphasic devices?

• A. Typically 200 J (range 120-200 J)
• B. 120 J
• C. 360 J
• D. 100 J

Answer: (A)

Biphasic defibrillators deliver energy more efficiently, using two current directions, which allows successful defibrillation with lower energy while reducing myocardial injury. Because of this, the typical starting energy for a first shock on modern biphasic devices is around 200 J. The range of 120–200 J accounts for differences between specific devices and manufacturer presets. Higher energies like 360 J were common with older monophasic shocks, whereas 100–120 J would be considered too low for a standard initial biphasic shock. So, 200 J is the best starting point because it balances effectiveness with safety across most devices.